Interview With Father Thomas Berg of Westchester Institute
Seeking an Ethical Option to Embryonic Stem Cell Research
NEW YORK, JUNE 13, 2005 (Zenit.org). - Legionary of Christ Father Thomas Berg, a leading Catholic ethicist on embryonic stem cell research and executive director of the Westchester Institute, a Catholic ethics think tank located in suburban New York, sees hope for a process known as altered nuclear transfer. He gave an overview of the status of stem cell research in this interview with ZENIT.
Q: What is the ethical problem with embryonic stem cell research?
Father Berg: The problem is that the methods currently used to obtain these cells -- pluripotent stem cells -- require researchers to kill living human embryos in the process.
In the case of so-called therapeutic cloning, which has been accomplished twice and recently streamlined by a group of South Korean researchers, it requires the intentional creation of human embryos precisely for their destruction in the course of harvesting stem cells from them.
Q: Are not human adult stem cells sufficient for all the therapeutic purposes we could want?
Father Berg: We really can't say enough in praising and promoting the inroads that have been made in developing therapies from adult stem cells.
Decades of research have yielded some 70 diverse therapies and clinical applications in treating diseases and disorders, including heart damage, spinal injury and several kinds of blood diseases.
By contrast, the research on deriving therapies from human embryonic stem cells is more nascent; it has only been going on in earnest for the last four or five years. Will it yield therapies? Quite possibly -- that's what scientists on both sides of the life issue tell me. It's too early to tell.
So, we should be guarded in our optimism with regard to the potential of adult stem cells.
Q: Can you explain again the difference between kinds of stem cells?
Father Berg: In the case of embryos, we distinguish between pluripotent and totipotent.
Pluripotent cells can give you -- to use an analogy with painting -- all the colors on the palette, but not the whole picture. That is to say, they give you all the human tissues.
Totipotent cells, on the other hand, can give you the whole picture -- a whole human being. It's the pluripotent cells that are of interest to the researchers.
Human adult stem cells are normally referred to as multipotent. There is ongoing debate as to whether certain kinds of adult stem cells -- for example, MAP-Cs, or multipotent adult progenitor cells -- can be coaxed to give rise to all tissue types. There are some reports that scientists are perhaps on the right trail, but no conclusive studies yet.
Q: How does cloning relate to stem cell research?
Father Berg: Cloning is the creation of a unique human individual through a process called somatic cell nuclear transfer. A donor donates a body cell from which the nucleus is taken and then transferred into an enucleated human egg. Factors in the cytoplasm of the egg are responsible for literally reprogramming the inserted nucleus to a pristine state, that of a one-cell human organism or zygote.
When coaxed with electrical stimulation, this clone begins to undergo the normal process of cell division which leads to the various stages of otherwise normal embryonic development. So the link with stem cell research is the following.
Cloning has been proposed as the ideal means of creating tailor-made embryonic stem cell lines. The DNA of the clone is an exact match of the donor's. The clone is developed to the blastocyst stage, about 6 days, at which point, its inner cell mass is extracted -- killing the human clone in the process.
From the inner cell mass of the clone are then derived in culture a new line of pluripotent stem cells which are a perfect genetic match to the donor. These lines of stem cells could be used to develop tissue replacement therapies for the donor -- should he or she eventually need them -- with no risk of immune rejection because the tissue is perfectly matched.
Q: Has anyone yet cloned a human being?
Father Berg: Yes. The South Korean team led by Woo Suk Hwang reported, in February 2004, the first successful creation of cloned human beings.
In 2004 they created some 30 embryos and allowed them to develop to the blastocyst stage. They were then destroyed in order to create lines of embryonic stem cells. On May 19 of this year, they reported that they have now honed their technique and claim to have created 11 new lines of human embryonic stem cells.
Q: Do you defend the Bush policy on funding of embryonic stem cell research?
Father Berg: While I am open to better arguments, I continue to defend the policy as the best prudential judgment President Bush could have made at the time.
You will recall that it was his decision on Aug. 9, 2001, to allow federal funding of research using lines of human embryonic stem cells created prior to Aug. 9. The president clearly demonstrated his moral condemnation of the evil of embryo destruction which was entailed in the creation of those lines. By this policy, he assured that no federal money would contribute to any new killing of embryos.
I think in hindsight we can make the case that by allowing a trickle of funding, he was able to forestall the evil that is now coming up on us. Had he completely banned federal funding, there would have been an extreme reaction from the scientific sector which would have provoked perhaps considerably more state and private funding. That's what is finally happening now.
Q: Are there morally acceptable means of obtaining human embryonic stem cells?
Father Berg: If it were shown to be feasible to obtain pluripotent stem cells by ethically acceptable means, I would support and encourage scientific exploration of their potential therapeutic value. The President's Council on Bioethics recently released a white paper exploring several possible alternative means.
Q: Can you briefly explain these alternative means for obtaining human pluripotent stem cells as described recently by the President's Council on bioethics?
Father Berg: That paper reported on, and gave an initial ethical evaluation of, four proposals for obtaining pluripotent stem cells without killing human embryos. The proposals are as follows in simple terms.
The first was proposed by Dr. Don Landry and Dr. Howard Zucker, both of Columbia University. They would seek to obtain embryonic stem cells from embryos that have been determined to be clinically "dead" in IVF [in vitro fertilization] clinics and that are about to be disposed of.
The second would perform a biopsy on an eight-cell embryo to remove an early forming stem cell, presumably without harming the embryo.
The third, called altered nuclear transfer, ANT, and proposed by Dr. William Hurlbut of Stanford University is to create a non-embryonic biological artifact akin to a tumor that would nonetheless produce the equivalent of pluripotent stem cells.
And the fourth proposal would endeavor to convert adult cells into pluripotent stem cells by reprogramming the nucleus of the adult cell to a pluripotent state. While the bioethics council could not endorse the "biopsy" proposal, it did encourage the pursuit of research on the other proposals using animal models.
Q: Why pursue these alternative means for obtaining embryonic stem cells?
Father Berg: I think in light of the fact that we now live in Brave New World, in which embryos are being created en masse, and in which there will be a growing demand for new embryonic stem cell lines, I believe we have a moral obligation to look seriously at alternate routes to obtaining them through non-embryo destructive means.
Q: Is there a down side to pursuing any of these proposals?
Father Berg: Potentially, and that's what makes them complicated from the moral perspective and that's why we need to see the animal studies done for these proposals.
With ANT, we have to be able to arrive at the moral certainty that the product of ANT is not an embryo; it may also run the risk of indirectly fomenting whole new avenues of human engineering.
The Zucker-Landry proposal may risk opening up a new market for the IVF industry, since it proposes removing intact embryonic stem cells from IVF embryos about to be discarded. But again, we may well have sufficient reason to tolerate the chances of any of this happening.
Q: You are on public record as supporting Dr. Hurlbut's proposal, ANT. Is that correct?
Father Berg: Yes. I, along with several other ethicists, have recently endorsed pursuing ANT on animal models -- not with human cells -- especially in a more recent and very specific rendition of ANT called oocyte assisted reprogramming.
Q: How did you get involved with Dr. Hurlbut?
Father Berg: When I thought carefully about what he was proposing, I felt we had almost a moral obligation to study his proposal seriously, so I contacted him about the possibility of getting some scholars together to look at the moral side of the proposal. That was last December.
Q: Explain altered nuclear transfer and new version you referred to called oocyte assisted reprogramming.
Father Berg: ANT is a broad conceptual proposal and could be accomplished in many different ways. The steps involved in oocyte assisted reprogramming would be the following.
First, a cell is removed from a donor and the DNA in the nucleus of that cell is "altered" in an effort to change the instructions that this nucleus would be giving to the cell, keeping in mind that a cell's nucleus essentially determines what kind of cell it will be.
Then, the nucleus is removed from an oocyte, or egg cell, and this enucleated oocyte, now essentially a sack of cytoplasm, is fused to the donor cell with the altered nucleus.
This process of cell fusion -- also called nuclear transfer -- is the same has used in cloning, but the product would be radically different in this case. This newly constituted cell would neither be an egg, nor an embryo, nor would it any longer be the cell it once was.
Rather, it would now be a hybrid that would show or express the properties programmed into it by the changes made to the nucleus. The way the scientist in our working group have conceived of it would suggest that the new cell would be programmed to essentially act like and produce pluripotent stem cells.
These stem cells would be genetically identical to the donor and could conceivably be used for research and therapeutic purposes. So essentially, it would mean going from an adult cell to stem cells, bypassing the creation and destruction of embryos in the process.
So, the long and the short of it is that a growing number of scientists are quite confident that ANT-OAR would actively and immediately convert adult cells directly into pluripotent stem cells without generating embryos.
Q: So what exactly does the egg do in this process?
Father Berg: The egg's cytoplasm will strip the cellular type of the adult cell nucleus, reverting to an undifferentiated, more plastic, and virginal state as it were.
Yet, unlike cloning, the adult cell nucleus will not be converted to a totipotent state -- a state that could generate a whole human embryonic organism. Rather, should the ANT-OAR proposal work, the alterations made to the donor nucleus will ensure that the cell produced is not an embryo, and will immediately be able to multiply itself, producing a new line of pluripotent stem cells.
Q: Some people would wonder if ANT does not entail complicity in the evil of human embryonic stem cell research. They might ask: Why mess with human eggs and genetic material?
Father Berg: We all share a sense of profound veneration and respect to be owed to those elements -- human eggs, sperm, human genetic material -- that are the essentials of human life.
Nonetheless, their use for human benefit is not something intrinsically evil. In other words, while we don't go at it lightly, we have to recognize that there can be legitimate and morally unproblematic uses for them.
As long as in using human eggs, human genetic material does not in itself cause us to transgress some absolute moral norm, such as the norm prohibiting the creation or destruction of embryos, and as long as it is pursued in light of some substantial and probable benefit, then such research could proceed.
Could there be some foreseeable downside of doing this? For example, does it contribute to a thinning out of our respect of life? That is hypothetical, but even were that the case, I think in light of the fact that we now live in Brave New World, in which embryos are being created en masse, and in which there will be a growing demand for new embryonic stem cell lines, we have proportional reason to pursue this research and to tolerate the potential negative consequences.
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